Prepare a liter of fresh milk. 150G cup of yogurt (it is best to choose high calcium and low fat drops, because it is healthy) and put it at room temperature.

2. Prepare a glass bottle and a stirring rod. Wash them with boiling water and disinfect them.

3. Soak fresh milk in hot water for a while until the milk is warm, about 30-40 degrees, because this temperature is very suitable for the reproduction of lactic acid bacteria.

4. Pour the warm milk into the sterilized glass bottle, put 150G yogurt into it, and stir well.

5. Then cover it with safety film.

6. Put it in the oven, the temperature is about 30-40 degrees. Too high or too low is not suitable for the growth of lactic acid bacteria.

7. Take it out after six hours.